Fuze for a nongyratory projectile

ABSTRACT

THE FUZE, E.G. FOR A MORTAR, CAN BE DETONATED INSTANTANEOUSLY ON IMPACT OR, BY PREVIOUS ADJUSTMENT, WITH A TIME DELAY, THE FUZE HAS A PRIMARY FUSE FOR DETONATION ON IMPACT BY A FIRING PIN BUT IS HELD SPACED FROM THE LATTER BY A LOCKING DEVICE WHICH CAN BE UNLOCKED BY THE AXIAL ACCELERATION DUE TO DEPARTURE OF THE SHOT. THE FUZE ALSO HAS A DETONATOR SAFETY DEVICE COMPRISING A SECONDARY FUSE AND A HOLDER MOVABLE TRANSVERSALLY TO THE AXIS OF THE FUZE TO BRING THE SECONDARY FUSE OPPOSITE THE DETONATOR. TIME DELAY OF THE SECONDARY FUSE IS PROVIDED BY A CLOCKWORK MOVEMENT ROTATING A TOOTHED SECTOR. A SECOND FIRING PIN FOR THE SECONDARY FUSE ACTS AS A STOP BLOCKING THE   TOOTHED SECTOR IN INACTIVE POSITION. THE SECOND FIRING PIN IS BORNE BY A PLUNGER SLIDABLE AXIALLY IN THE FUZE. A BALL BLOCKING MECHANISM FIXES THE PRIMARY FUSE HOLDER AND THE PLUNGER RIGIDLY TO ONE ANOTHER AS LONG AS THE PROJECTILE HAS NOT UDERGONE IMPACT AFTER DEPARTURE OF THE SLOT. IMPACT RELEASES THE BLOCKING BALLS ENABLING THE PLUNGER AND THUS THE SECOND FIRING PIN TO BE DRIVEN BACK BY A SPRING, WITH THE TIME DELAY, AGAINST THE SECONDARY FUSE.

Feb. 13, 1973 R. MOREL ErAL 3,715,987

FUZE FOR A NONGYRATORY PROJECTILE Filed April 21, 1971 9 Sheets-Sheet 6INVENTORS PEA/5' 010/251. 72032127 .S/nmm/ BY am z. W.

ATTORNEY Feb. 13, 1973 R. MOREL. ETAL 3,715,987

FUZE FOR A NONGYRATORY PROJECTILE Filed April 21, 1971 9 Sheets-Sheet 7INVENTORS PEA E M025!- RaaEET S/MMEA/ BY WC'DRNEY Feb. 13, 1973 R. MORELETAL 3,715,987

OOOOOOOOOOOOOOOOOOOOOOOOOOO LE Filed April 2 1 l 9 71 Feb. 13, 1973 RMQREL ETAL 3,715,987

FUZE FOR A NONGYRATORY PROJECTILE Filed April 21, 1971 9 Sheets-Sheet 9INVENTOR I? maAEEL 20 E T S/MMEN RNEY 3,715,987 FUZE FOR A NUNGYRATORYPROJECTILE Reu Morel and Robert Simmen, Geneva, Switzerland, assignorsto Mefina S.A., Fribourg, Switzerland Filed Apr. 21, 1971, Ser. No.136,065 Claims priority, application Switzerland, May 14, 1970, 7,240/70Int. Cl. F42c 1/08 US. Cl. 102-74 Claims ABSTRACT OF THE DISCLOSURE Thefuze, e.g. for a mortar, can be detonated instantaneously on impact or,by previous adjustment, with a time delay. The fuze has a primary fusefor detonation on impact by a firing pin but is held spaced from thelatter by a locking device which can be unlocked by the axialacceleration due to departure of the shot. The fuze also has a detonatorsafety device comprising a secondary fuse and a holder movabletransversally to the axis of the fuze to bring the secondary fuseopposite the detonator. Time delay of the secondary fuse is provided bya clockwork movement rotating a toothed sector. A second firing pin forthe secondary fuse acts as a stop blocking the toothed sector ininactive position. The second firing pin is borne by a plunger slidableaxially in the fuze. A ball blocking mechanism fixes the primary fuseholder and the plunger rigidly to one another as long as the projectilehas not undergone impact after the departure of the shot. Impactreleases the blocking balls enabling the plunger and thus the secondfiring pin to be driven back by a spring, with the time delay, againstthe secondary fuse.

The present invention relates to a fuze for a nongyratory projectile,especially for firing by a mortar, enabling instantaneous detonation ofthe projectile on impact, or delayed detonation by previous adjustmentof the fuze, the latter comprising a primary fuse or initiator fordetonation on impact by driving in a firing pin, this primary fuse beingfixed to a primary fuse holder subject to the action of a spring tendingto push it axially into armed position towards the firing pin, but heldin spaced position from the latter by a locking device capable of beingunlocked under the action of axial acceleration due to departure of theshot, this fuze comprising also a detonator safety device comprising asecondary fuse or initiator fixed to a secondary fuse holdertransversally movable with respect to the axis of the fuze, subject tothe action of a spring tending to bring the secondary fuse opposite thedetonator, a clockwise movement controlling the passage of the secondaryfuse holder from its secured position to its armed position, thisclockwork movement comprising a toothed sector subject to the action ofthe spring, a stop displaceableaxially on departure of the shot lockingthis toothed sector in inactive position of the fuze.

Projectile fuzes, of the type defined above, are generally of verycomplicated and expensive construction. For this reason, known fuzes ofthis type run the risk of faulty operation resulting either from anerror of assembly, or from locking or binding of a delicate part.

It is an object of the invention to provide a fuze which overcomes theaforesaid drawbacks.

The fuze according to the invention is characterized by the fact thatthe stop blocking the toothed sector in inactive position of the fuze isformed by a second firing pin capable of firing the secondary fuse oncethe latter is in armed position, the second firing pin being borne by aplunger or ram capable of sliding axially in the primary fuse holderagainst the action of a spring, a ball blocking mechanism rendering theprimary fuse holder and the 3,715,987 Patented Feb. 13, 1973 saidplunger rigidly fixed to one another as long as the projectile has notundergone impact after the departure of the shot, such impact causingthe escape of the blocking balls enabling the plunger and, thus, thesecond firing pin, to be driven back by their spring, with delay,against the secondary fuse.

In order that the invention may be more fully understood, one embodimentof the fuze according to the invention is described below, purely by wayof illustrative but non-limiting example, with reference to theaccompanying drawings, in which:

FIG. 1 is a view in elevation, in axial section, showing an embodimentof the fuze according to the invention in secured inactive position,

FIG. 2 is a view similar to that of FIG. 1 showing the fuze afterdeparture of the shot, that is to say after emerging from the ordnancepiece,

FIG. 3 is a view similar to the preceding views, showing the fuze at themoment of instantaneous ignition following an impact,

FIG. 4 is a view similar to the preceding views, showing the fuze inposition after having undergone impact, when it has been adjusted fordelayed detonation,

FIG. 5 is a view similar to the preceding views, showing the fuze indelayed firing position,

FIGS. 6 to 8 are views in section along the line A-A of FIG. 1, showingthe three positions of adjustment of the fuze, that is to sayrespectively: the adjustment position for instantaneous detonation onimpact: secured position of the fuze; and adjusted position for delayeddetonation, after impact,

FIGS. 9 and 10 are sections along the line B-B of FIG. 1,

FIG. 9 corresponding to the secured position, whilst FIG. 10 correspondsto the delayed detonation,

FIG. 11 is a view in section along the line C-C of FIG. 1, showing thetrajectory safety device in unarmed position, and

FIG. 12 is a section along the line D-D of FIG. 2, showing thetrajectory safety device in armed position.

Referring to the drawings, the uongyratory projectile fuze showncomprises a body formed of a lower tubular part I screwed inside a part2 in the general shape of a cap. In the lower end 3 of the part 1 isscrewed a part 4 forming a plug and bearing the detonator 5 and itstransmitting charge 6.

The part 2 has a cylindrical collar 7 on which is totatably mounted anogive-shaped part 8. This part 8 is held on the collar 7 due to screws 9engaged in holes 10 tapped radially in the part 8. These screws 9 havean end portion 11 of smooth cylindrical shape engaged in a peripheralgroove 12 of the part 2.

A bore 13 is arranged in the upper end portion of the part 8 to receivea cylindrical ram 14 rigidly fixed to a firing pin 15 arranged in theaxis of the fuze. The point of this firing pin 15 is capable ofpenetrating into a bore 16 of the part 2 through an opening 17. However,this firing pin 15 has a part 18 of rectangular section (see FIGS. 6 to8) whose large transverse dimension is greater than the width of thepassage 17 which is of general rectangular shape. In the position shownin FIGS. 1 to 8, the firing pin 15 cannot thus be driven into the bore16. On the other hand, in the case of relative angular displacementbetween the firing pin 15 and the part 2, it is possible to bring thepart 18 of the firing pin 15 into correspondence with the rectangularpassage 17, this position being precisely the position provided forinstantaneous detonation of the fuze on impact.

The firing pin 15 is rigidly fixed angularly to the ogiveshaped part 8by means of pins 19 driven radially into apertures 20 of the part 8, theend 21 of these pins 19 3 being engaged in a corresponding axial slot 22arranged in the ram 14 bearing the firing pin 15. These slots 22 henceenable axial movement of the ram 14, but render the latter angularlyrigid with the part 8.

This ram 14 has an internal bore 23 inside of which is housed the spring24 constituting the return spring of the firing pin 15. This spring 24is supported at one of its ends against the bottom of the bore 23,whilst its other end is engaged around a collar 25 extending the part 2and surrounding the portion 18 of the firing pin 15. The spring 24 issupported by this end against the upper face 26- of the part 2 forming aportion of the body of the fuze.

A protecting cap 27 covers the upper portion of the ogive-shaped part 8and is held on the latter by means of a peripheral bead 28 engaged in agroove 29 of the part 8.

The part 2 of the body of the fuze has an inner bore 30 located in theextension of an inner bore 31 arranged in the part 1. Inside these twobores 30 and 3 1 is arranged a sleeve 32 guided axially in the :bore 31.The upper part 33 of this sleeve 32 is of reduced diameter and bears thepri mary fuse 34 which must be ignited by the firing pin 15. This sleeve32 hence constitutes in fact the primary fuse holder of the fuze. Thissleeve 32 is subject to the action of a spring 35 supported on one handagainst a shoulder 36 of the sleeve 32 and, on the other hand, against ashoulder 37 arranged in the bottom of the bore 31. This spring 35 hencetends to return forward, that is to say towards the firing pin 15, theprimary fuse holder 32, 33, 34. However, a locking device holds thisprimary fuse holder 32-34 in secured position, spaced from the firingpin 15. This locking device comprises a ring 3% bearing elastic tongues39 with thickened ends 40. This ring 38 is arranged in the upper portionof the bore 30. It has also a peripheral shoulder 41 enabling a bolt 42to retain this ring 38 in secured position. The thckened ends of theelastic tongues 39 are capable of being engaged successively in twogrooves 43 and 44, spaced axially on the portion 33 of the primary fuseholder sleeve 32-34. A ring or bushing 45 subject to the action of thespring 46 surrounds the tongues 39. This bushing 45 has a portion 47bored to a larger diameter than the end portion 48. As long as theportion 43 is at the level of the thickened ends 40 of the tongues 39,the latter cannot be disengaged from the groove 43. On the other hand,if following an axial displacement of the bushing 45, the portion 47occurs opposite the thick end parts 40, the latter are elasticallyseparable and can pass from the groove 43 into the groove 44 following arelative axial displacement between the sleeve 32, 33 and the ring 38,and this specially on the departure of the shot. However, such an axialdisplacement of the ring 38 is prevented by the bolt 42 as long as thelatter holds the shoulder 41 of this ring 33. This bolt 42 is in theshape of a piston slidably radially in a hole 49 arranged in the collar7 of the part 2. This piston shaped 'bolt 42 is subject to the action ofa leaf spring 50 tending to extract it from the hole 49 and thus toliberate the shoulder 41 of the ring 38. However, such a radialextraction movement of the bolt 42 is rendered impossible as long as thelatter is supported by its rounded end 51 against the internal bore 52of the cap 8. However, two cavities 53 and 54 (see FIGS. 9 and 10) arearranged in this bore 52 on both sides of the position occupied by thebolt 42 in FIG. 9, which position corresponds to the secured position ofthe fuze. This position corresponds therefore to the position ofstorage, transport or handling of the projectile. It will be understoodwithout elaboration, on a study of FIGS. 9 and 10, that in causing anangular displacement, through a certain angle, of the cap 8, it ispossible to bring either the cavity 52, or the cavity 54 opposite thehole 49, which enables the bolt 42 to escape radially to occupy theposition shown in FIG. 10 which corresponds to the adjustment fordelayed detonation after impact of the fuze. To this position shown inFIG. 10 corresponds the position shown in PIC}. 8 of the firing pin 15and of its portion 18 especially with respect to passage 17.

Inside the sleeve 32 constituting the primary fuse holder is arranged aplunger or ram 55 slidable in this sleeve 32 against the action of aspring 56 tending to return the ram 55 away from the primary fuse 34.This ram 55 carries a second firing pin 57. In addition, a channel 58 isarranged in this ram 55 to enable the passage of the flame provided fromthe primary fuse 34 in the direction of a secondary fuse 59 arranged inthe lower portion of the fuze.

A ball blocking mechanism 60 enables the primary fuse holder 32-34 andthe ram 55 to be rigidly fixed to one another. In fact, the sleeve 32 ofthe primary fuse holder 32-34 has radial passages 61 of which the axisis directed towards the front of the fuze, from the center of thelatter. On the other hand, the ram 55 has hemispherical recesses 62intended to serve for partial housing of the balls 60. Through thisfact, as long as the outer opening of the passages 61 is facing the bore31 of the part 1 of the body of the fuze, the balls 60 are held partlyin the ram 55 and partly in said passages 61, which locks the parts 32and 55 with respect to one another. However, a peripheral groove 63 isarranged in the upper portion of the bore 31, this groove being intendedto receive the balls 69 after the fuse holder 32-34 has undergonedisplacement towards the front against the action of the spring 46. Sucha displacement is produced on impact of the projectile against thetarget (see FIGS. 2 to 5).

The secondary fuse 59 is carried by a fuse holder 64 mounted tooscillate around an axle 65 parallel to the axis of the fuze, this axlebeing fixed between two plates 66 and 67 of a clockwork movement. Atong-shaped spring 68 engaged around the axle 65 tends to make thesecondary fuse holder 64 pivot in anti-clockwise direction with respectto FIGS. 11 and 12 to bring the secondary fuse 59 into the axis of thefuze, so that it coincides with the position of the second firing pin 57(see FIG. 12). However, this displacement of the secondary fuse holder64 is prevented by a bolt 69 in the shape of a rod subject to the actionof the spring 70, this rod 69 and this spring 70 being arranged in ahousing 71 provided in the secondary fuse holder 64. One end 72 of thisrod 69 is engaged in a hole 73 provided in the plate 66, rigidly fixedto the body of the fuze, whilst the other end '74 of this rod 69 cannotescape upwardly. In fact, this end 74 is supported against a toothedsector 75 mounted to oscillate around the same axle 65 and subject tothe action of a tong spring 76 engaged around a tubular portion 77rigidly fixed to this toothed sector 75. This spring 76 is engagedbetween a column 78 linking two plates 66 and 67 and a pin 79 borne bythe toothed sector 75. It is only after angular displacement of thetoothed sector 75 from the position shown in FIG. 11 to the positionshown in FIG. 12 and slightly before the toothed sector 75 reaches thislatter position that the end 74 can escape from this toothed sector andenable the spring 70 to extract the end 72 of the rod 69 from the hole73, which then frees the secondary fuse holder 64 which is displaced byits spring 68 into the position shown in FIG. 12 in which the secondaryfuse 59 occurs in the axis, that is to say in the detonation position inthe fuze. The displacement of the toothed sector 75 is only possibleafter displacement in the direction of the nose of the fuze of the ram55 and of the firing pin 57 which constitute a stop for the pin 79, insecured position of the fuze. After such a forward displacement of theram 55, that is to say after the departure of the shot (see FIG. 2), themovement of the toothed sector 75 is braked by the escape wheel 80 andbalance lever 81 of the clockwork movement mounted to oscillate aroundan axle 82. This escape wheel 80 is rigidly fixed to a pinion 83 withwhich the toothed sector 75 meshes by its teeth 84. The escape wheel 80and the pinion 83 constitute a rotary drive mounted by axles on pivots85 and 86 in plates 66 and 67.

The fuze described above is intended to be fixed in the front portion ofa projectile by screwing the threaded portion 87 of the body of the fuzein a shell body for example, so that the detonator is close to theexplosive charge of the projectile.

The operation of the fuze described above is as follows:

When the fuze is in inactive position, that is to say in position ofstorage or transport, the part 8 forming the ogive is adjusted into theposition shown in FIG. 9, for which position the bore 52 prevents thebolt 42 from escaping radially, which causes the ring 38 to be held byits shoulder 41 in its extreme position towards the front of the fuze,the tongues 39 blocked by the ring 45 holding the primary fuse holder32-34 in the position shown in FIG. 1, for which position this primaryfuse 34 is separated from the firing pin 15 itself held in inactiveposition,.its. point being engaged in the passage17 in the angularposition corresponding to FIG. 7, preventing any displacement of the pin15 in the direction of the primary fuse 34. On the other hand, the ram55 is kept blocked with respect to the sleeve 32 by the balls 60. Thus,the second firing pin 57 retains the toothed sector 75 in securedposition by its pin 79. In addition, the rod 69 blocks the secondaryfuse holder 64.

When an instantaneous explosion of the projectile on impact is required,the ogive 8 is brought into the angular position corresponding to theplacing in coincidence of the cavity 54 with the hole 49. As soon asthis operation has been effected, the bolt 42 escapes radially and freesthe shoulder 41 of the ring 38. Moreover, the angular displacement ofthe ogive 8 brings the firing pin 15 and especially its portion 18 intothe position shown in FIG. 6, that is to say into a position enablingpassage of this portion 18 into the rectangular opening 17.

On the departure of the shot, in the muzzle, for example in a mortar,the ring 45 is driven rearward against the action of the spring 46 whichenables the ring 38 bearing tongues 39 to be displaced also towards therear, the ends 40 of the tongues 39 escaping from the groove 43 to beengaged in the groove 44. On emergence of the projectile from themuzzle, the spring 46 pels towards the front, the ring 45, which againlocks the tongues 39 engaged then in the groove 44. The spring 35 alsopushes back towards the front the fuse holder 32-34, driving with it theram 55 which is rendered rigidly fixed to it by the balls 60 heldengaged in the recesses 62 of the ram 55 due to the inclination towardsthe front of the passages 61 provided in the sleeve 32. The primary fuse34 then reaches its armed position close to the point of the firing pin15. Simultaneously, the second firing pin 57 frees the pin 79 rigidlyfixed to the toothed sector 75, which enables the latter to commence itsangular displacement under the action of its spring 76, whichdisplacement is braked by the clockwork movement constituted by thepinion 83, the escape wheel 80 and the balance lever 81. The secondaryfuse holder 64 and its actuating mechanism constitutes in fact atrajectory safety device. When the toothed sector 75 has accomplishedits full displacement, the locking rod 69 having freed the secondaryfuse holder 64, this secondary fuse 59 is brought into armed position(see FIG. 12) by its spring 68. If at this moment the projectile reachesits target, the protective cap 27 is thrust down (see FIG. 3) and theram 14 is driven back towards the rear against the action of the spring24 thereby driving the firing pin 15 which detonates the primary fuse34. The flame is transmitted through the channel 58 to the secondaryfuse 59 which, in its turn, detonates the transmission charge 6, thedetonator 5 and the charge of the projectile.

If the projectile has to explode with delay after impact, the ogive 8 isdisplaced angularly with respect to the body of the fuze, so that thecavity 53 is brought opposite the hole 49 so as to permit escape of thebolt 42 into the position shown in FIG. 10. This adjustment brings thepart 18 of the firing pin 15 into transverse position with respect tothe rectangular passage 17 (FIG. 8), which prevents any possibility ofdisplacement of the firing pin 15 in the direction of the primary fuse34.

On firing of the projectile in the muzzle, and as explained previously,the ring 45 and then the ring 38 bearing tongues 39, come to be engagedin position opposite the groove 44. On emergence from the muzzle, theprimary fuse holder 3234 is driven forward by the spring 35, so that thepin 79 is released by the second firing pin 57, which enables theoperation of the trajectory safety device, that is to say which permitsdisplacement of the toothed sector 75 and then the bringing into armedposition of the secondary fuse 59. On impact of the projectile, theprotective cap 27 is driven down (see FIG. 4) and the arm 14 is thrusttowards the rear, the rod 88 of the firing pin 15 being buckled by thismovement of theram 14, given that the. point ofthe firing pin 15 is heldby the portion 18 arranged transversally with respect to the rectangularpassage 17. Through this fact, no firing, no firing of the primary fuse34 is produced. On the other hand, under the effect of this impact, theplunger or ram 55 is driven forwards against the action of the spring56, the balls 60 being ejected into the groove 63 then serving ashousing for them with the passages 61. Then, the spring 56 pushes backrearwards the plunger or ram 55 and the second firing pin 57 whichcauses the delayed detonation of the secondary fuse 59 (see FIG. 5).

The preceding description shows that this fuse is of simple conceptionenabling with a minimum of machined parts the obtaining of a verycompact construction having high operational safety with the possibilityof either instantaneous or delayed detonation of the charge of theprojectile.

It will be apparent that various changes and modifications may be madein the embodiment described with out departing from the invention asdefined in scope by the appended claims.

We claim:

1. Fuze for a nongyratory projectile, especially for firing by a mortar,enabling either instantaneous detonation of the projectile on impact ordelayed detonation by prior adjustment of the fuze, said fuzecomprising:

a fuze body,

a detonator,

a primary fuse,

a first firing pin arranged to be driven into said primary fuse fordetonation on impact,

a primary fuse holder holding said primary fuse subject to the action ofa first spring tending to thrust it axially in armed position towardssaid first firing p a locking device adapted to be unlocked under theeffect of axial acceleration due to the departure of the shot andmaintaining said primary fuse holder in spaced position from said firstfiring pin,

a detonator safety device comprising a secondary fuse,

a secondary fuse holder holding said secondary fuse transversallymovable with respect to the axis of the fuze, a second spring tending tobring the secondary fuse opposite the detonator, clockwork meanscontrolling the passage of the secondary fuse holder from a safetyposition to an armed position,

said clockwork means comprising a toothed sector subject to the actionof a third spring, a stop axially displaceable on departure of the shotlocking said toothed sector in inactive position of the fuze, a secondfiring pin forming said stop and arranged to detonate the secondary fuseonce the latter is in armed position, a plunger axially slidable in theprimary fuse holder against the action of a fourth spring and bearingsaid second firing pin, and a ball blocking mechanism arranged to fixsaid primary fuse holder and said plunger rigidly to one another as longas the projectile has not been subjected to an impact after thedeparture of the shot, and on such impact, to cause the escape of theblocking balls enabling the plunger and thus the second firing pin, tobe driven in by their spring, with a time delay, against the secondaryfuse.

2. Fuze according to claim 1, wherein the primary fuse holder is in theform of a sleeve capable of sliding axially in a bore of the fuze bodyhaving a peripheral groove, the balls of the blocking mechanism beingnormally housed partly in corresponding recesses of the plunger andpartly in radial passages arranged in the said primary fuse holdersleeve, said peripheral groove being adapted to receive the balls afterthe impact of the projectile.

3. Fuze according to claim 2, wherein the axis of said radial passagesis directed towards the front of the fuze, from the center of thelatter, so that the balls remain clamped between the plunger and theradial passages until impact, under the action of said fourth spring.

4. Fuze according to claim 1, wherein the locking device of the primaryfuse holder comprises an annulus bearing tongues with thickened ends,two axially spaced grooves being arranged in the outer wall of theprimary fuse holder, said thickened ends being engaged in one of saidgrooves, a ring subject to the action of a fifth spring encasing saidtongues so as only to permit passage of the tongues from one to theother of the two grooves on axial acceleration of the projectile ondeparture of the shot after relative axial displacement of the ring withrespect to the annulus bearing the tongues.

5. Fuze according to claim 1, wherein the secondary fuse holder ismounted to oscillate around an axis parallel to the axis of the fuze,the toothed sector being mounted to oscillate around the same axis, abolt formed by a rod subject to the action of a sixth spring beingarranged in a housing of the secondary fuse holder so that one end ofsaid rod is engaged in a hole in a part rigidly fixed to the body of thefuze and locks the secondary fuse holder in safety position as long asthe other end of the rod is supported against a surface of the toothedsector.

6. Fuze according to claim 2, wherein the locking device of the primaryfuse holder comprises an annulus bearing tongues with thickened ends,two axially spaced grooves being arranged in the outer wall of theprimary fuse holder, said thickened ends being engaged in one of saidgrooves, a ring subject to the action of a fifth spring encasing saidtongues so as only to permit passage of the tongues from one to theother of the two grooves on axial acceleration of the projectile ondeparture of the shot after relative axial displacement of the ring withrespect to the annulus bearing the tongues.

7. Fuze according to claim 3, wherein the locking device of the primaryfuse holder comprises an annulus bearing tongues with thickened ends,two axially spaced grooves being arranged in the outer Wall of theprimary fuse holder, said thickened ends being engaged in one of saidgrooves, 21 ring subject to the action of a fifth spring encasing saidtongues so as only to permit passage of the tongues from one to theother of the two grooves on axial acceleration of the projectile ondeparture of the shot after relative axial displacement of the ring withrespect to the annulus bearing the tongues.

8. Fuze according to claim 2, wherein the secondary fuse holder ismounted to oscillate around an axis parallel to the axis of the fuze,the toothed sector being mounted to oscillate around the same axis, abolt formed by a rod subject to the action of a sixth spring beingarranged in a housing of the secondary fuse holder so that one end ofsaid rod is engaged in a hole in a part rigidly fixed to the body of thefuze and locks the secondary fuse holder in safety position as long asthe other end of the rod is supported against a surface of the toothedsector.

9. Fuze according to claim 3, wherein the secondary fuse holder ismounted to oscillate around an axis parallel to the axis of the fuze,the toothed sector being mounted to oscillate around the same axis, abolt formed by a rod subject to the action of a sixth spring beingarranged in a housing of the secondary fuse holder so that one end ofsaid rod is engaged in a hole in a part rigidly fixed to the body of thefuze and locks the secondary fuse holder in safety position as long asthe other end of the rod is supported against a surface of the toothedsector.

10. Fuze according to claim 4, wherein the secondary fuse holder ismounted to oscillate around an axis parallel to the axis of the fuze,the toothed sector being mounted to oscillate around the same axis, abolt formed by a rod subject to the action of a sixth spring beingarranged in a housing of the secondary fuse holder so that one end ofsaid rod is engaged in a hole in a part rigidly fixed to the body of thefuze and locks the secondary fuse holder in safety position as long asthe other end of the rod is supported against a surface of the toothedsector.

References Cited UNITED STATES PATENTS 1,547,599 7/1925 Lukens l02741,648,603 11/1927 Barker 10274 2,173,620 9/1939 Brayton 10274 2,324,1927/1943 Brayton 102-74 2,977,882 4/1961 Vasse 102-74 2,999,461 9/1961Apotheloz et a1. 102-75 3,115,094 12/1963 Simrnen 10 274 SAMUEL W.ENGLE, Primary Examiner U.S. c1. x12. 10276 R, 84

